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Acta Cryst. (2010). E66, m520-m521    [ doi:10.1107/S1600536810013061 ]

Hexaaquamanganese(II) bis{[N-(3-methoxy-2-oxidobenzylidene)glycylglycinato]copper(II)} hexahydrate

L.-W. Lei, Y.-Z. Jiang and Y. Zou

Abstract top

The ligand N-(2-hydroxy-3-methoxybenzylidene)glycylglycine (H3L), a Schiff base derived from glycylglycine and 3-methoxysalicylaldehyde, was used in the synthesis of a new organic-inorganic coordination complex, [Mn(H2O)6][Cu(C12H11N2O5)]2·6H2O. The MnII atom is located on an inversion center and is coordinated to six water molecules in a slightly distorted octahedral geometry. The CuII atom is chelated by the tetradentate Schiff base ligand in a distorted CuN2O2 square-planar coordination. In the crystal structure, the complex [Mn(H2O)6]2+ cations and the [CuL]- anions are arranged in columns parallel to the a axis and are held together by O-H...O hydrogen bonding. Additional hydrogen bonds of the same type further link the columns into a three-dimensional network.

Comment top

Transition metal complexes of salicylaldehyde-peptides and salicylaldehyde-amino acid Schiff-bases are non-enzymatic models for pyridoxal-amino acid systems, which are of considerable importance as key intermediates in many metabolic reactions of amino acids catalyzed by enzymes (Zabinski et al., 2001; Wetmore et al., 2001; Bkouche-Waksman et al.,1988). Considerable effort has been devoted to the preparation, structural characterization, appropriate spectroscopic and magnetic studies of Schiff-base complexes derived from salicylaldehyde and amino acids and reduced salicylidene amino acids (Ganguly et al., 2008), but little attention has been devoted to Schiff bases derived from simple peptides (Zou et al., 2003). Herein, we report the structure study of [Mn(H2O)6][Cu(C12H11N2O5)]2.6H2O (H3L= Schiff base derived from glycylglycine and 3-methoxy-salicylaldehyde, C12H14N2O5).

The asymmetric unit of structure (I) consist of one-half of a [Mn(H2O)6]2+ cation (completed by crystallographic inversion symmetry), one [CuL]- anion and three water molecules (Fig. 1 and Table 1). The coordination environment of the CuII atoms is approximately square-planar. The Schiff-base ligand is deprotonated, thus acting as a triple negatively charged tetradentate ONNO chelate. It coordinates to the CuII atom via one phenolic oxygen atom (O2), one deprotonated amide nitrogen atom (N2), one imino nitrogen atom (N1) and one carboxylate oxygen atom (O4). The two Cu—N bond distances are 1.905 (5) Å (Cu1—N1) and 1.887 (5) Å (Cu1—N2). The two Cu—O bonds are 1.979 (4) (Cu1—O4) and 1.873 (4) Å (Cu1—O2). The phenyl ring [C1—C6] and the chelate ring [C1, C6, C7, N1, O2, Cu1] are almost coplanar with a small dihedral angle of 0.6°. The MnII center is octahedrally coordinated by the O atoms of six water molecules with Mn—O bond lengths in the range of 2.161 (4)-2.212 (4) Å.

Complex (I) shows an interesting stacking structure. The anions and cations of the complex form well-separated columns (Fig. 2) stacked along [100], held together by hydrogen bonding of the type O—H···O. The anion stacking is characterised by [CuL]- columns arranged in a zig-zag manner. The shortest Cu···Cu separation within a [CuL]- chain is 4.447 Å and the closest Cu···Cu separation between anionic chains is 9.312 Å. Additional O—H···O hydrogen bonds between the coordinated water molecules and uncoordinated water molecules further link the columns into a three-dimension network (Fig. 2, Table 1).

Related literature top

Transition metal complexes of salicylaldehyde-peptide and salicylaldehyde–amino acid derived Schiff bases are suitable non-enzymatic models for pyridoxal amino acid systems, which are of considerable importance as key intermediates in many metabolic reactions; see: Bkouche-Waksman et al. (1988); Wetmore et al. (2001); Zabinski & Toney (2001). For the preparation, structural characterization, spectroscopic and magnetic studies of Schiff base complexes derived from salicylaldehyde and amino acids, see: Ganguly et al. (2008) and references cited therein. For Schiff bases derived from simple peptides, see: Zou et al. (2003).

Experimental top

The Schiff base was prepared through the condensation of glycylglycine and 3-methoxy-salicylaldehyde. Glycylglycine (10 mmol) was dissolved and refluxed in absolute methanol (40 ml) containing LiOH.H2O (10 mmol). After cooling to room temperature, a solution of 3-methoxy-salicylaldehyde (10 mmol) in absolute methanol was added slowly under stirring for 10 min. Then Cu(NO3)2 (10 mmol) was added to the HLLi solution and the resulting solution was adjusted to pH = 9-11 by 1.0 mol/L NaOH solution. After stirring at room temperature for 30 min, the volume was reduced to ca. 5 ml in vacuo. Anhydrous ethanol was added to precipitate the product, which then was recrystallized in methanol solution. Na[CuL].2H2O (2 mmol) was dissolved in 10 ml water. Then MnCl2.4H2O (1 mmol) was added to the solution under stirring. The resulting crude product was precipitated. It was recrystallized in hot water 363 K and filtered. The filtrate was allowed to evaporate slowly at room temperature. After several days red to violet crystals suitable for X-ray diffraction were obtained.

Refinement top

The water H atoms in the complex were located in a difference Fourier map and were refined with a distance restraint of O—H = 0.85 Å and Uiso(H) = 1.5Ueq(O). All other H atoms were positioned geometrically and were constrained as riding atoms, with C—H distances of 0.93–0.97 Å and Uiso(H) set to 1.2 or 1.5Ueq(C) of the parent atom.

Computing details top

Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2000); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. ORTEP plot of the asymmetric unit of complex (I) with the atom-numbering scheme (ellipsoids are drawn at the 40% probability level).
[Figure 2] Fig. 2. Representation of the hydrogen-bonded three-dimensional network (dashed lines) in the crystal structure of compound (I).
Hexaaquamanganese(II) bis{[N-(3-methoxy-2-oxidobenzylidene)glycylglycinato]copper(II)} hexahydrate top
Crystal data top
[Mn(H2O)6][Cu(C12H11N2O5)]2·6H2OZ = 1
Mr = 924.67F(000) = 477
Triclinic, P1Dx = 1.682 Mg m−3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 6.712 (1) ÅCell parameters from 1625 reflections
b = 11.762 (2) Åθ = 1.7–25.0°
c = 12.092 (2) ŵ = 1.59 mm−1
α = 76.51 (1)°T = 293 K
β = 83.90 (1)°Block, violet-red
γ = 80.37 (1)°0.3 × 0.2 × 0.2 mm
V = 912.9 (3) Å3
Data collection top
Bruker SMART CCD
diffractometer		3156 independent reflections
Radiation source: fine-focus sealed tube1625 reflections with I > 2σ(I)
graphiteRint = 0.114
φ and ω scansθmax = 25.0°, θmin = 1.7°
Absorption correction: multi-scan
(SADABS; Bruker, 2003)		h = −7→7
Tmin = 0.690, Tmax = 0.728k = −12→13
4571 measured reflectionsl = −14→13
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.057Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.129H atoms treated by a mixture of independent and constrained refinement
S = 0.79 w = 1/[σ2(Fo2) + (0.0082P)2]
where P = (Fo2 + 2Fc2)/3
3156 reflections(Δ/σ)max < 0.001
246 parametersΔρmax = 0.74 e Å−3
114 restraintsΔρmin = −0.56 e Å−3
Crystal data top
[Mn(H2O)6][Cu(C12H11N2O5)]2·6H2Oγ = 80.37 (1)°
Mr = 924.67V = 912.9 (3) Å3
Triclinic, P1Z = 1
a = 6.712 (1) ÅMo Kα radiation
b = 11.762 (2) ŵ = 1.59 mm−1
c = 12.092 (2) ÅT = 293 K
α = 76.51 (1)°0.3 × 0.2 × 0.2 mm
β = 83.90 (1)°
Data collection top
Bruker SMART CCD
diffractometer		3156 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2003)		1625 reflections with I > 2σ(I)
Tmin = 0.690, Tmax = 0.728Rint = 0.114
4571 measured reflectionsθmax = 25.0°
Refinement top
R[F2 > 2σ(F2)] = 0.057H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.129Δρmax = 0.74 e Å−3
S = 0.79Δρmin = −0.56 e Å−3
3156 reflectionsAbsolute structure: ?
246 parametersFlack parameter: ?
114 restraintsRogers parameter: ?
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cu10.77185 (12)0.49742 (7)0.37778 (7)0.0309 (3)
C10.7114 (9)0.5700 (6)0.5897 (5)0.0359 (10)
C20.6755 (9)0.6598 (7)0.6508 (6)0.0396 (11)
C30.6653 (9)0.6330 (7)0.7685 (6)0.0407 (12)
H30.64210.69420.80710.049*
C40.6886 (9)0.5174 (6)0.8304 (6)0.0441 (13)
H40.67990.50070.90970.053*
C50.7244 (9)0.4286 (7)0.7730 (6)0.0430 (13)
H50.74060.35070.81430.052*
C60.7379 (9)0.4509 (6)0.6520 (5)0.0365 (11)
C70.7766 (9)0.3506 (6)0.6003 (5)0.0366 (12)
H70.78910.27610.64870.044*
C80.8340 (9)0.2463 (5)0.4483 (5)0.0332 (12)
H8A0.72530.19970.47580.040*
H8B0.95990.19920.47460.040*
C90.8469 (9)0.2797 (6)0.3194 (5)0.0311 (11)
C100.8264 (9)0.4476 (5)0.1580 (5)0.0283 (11)
H10A0.72420.42230.12210.034*
H10B0.95790.42450.12140.034*
C110.7866 (9)0.5805 (6)0.1443 (5)0.0296 (11)
C120.6232 (10)0.8684 (6)0.6400 (6)0.0542 (19)
H12A0.49730.86900.68570.081*
H12B0.62060.94120.58370.081*
H12C0.73250.86020.68780.081*
N10.7953 (7)0.3554 (5)0.4929 (4)0.0317 (10)
N20.8214 (7)0.3923 (4)0.2782 (4)0.0285 (10)
O10.6519 (6)0.7718 (4)0.5847 (4)0.0457 (11)
O20.7206 (6)0.6012 (4)0.4771 (4)0.0378 (10)
O30.8774 (6)0.1989 (4)0.2649 (4)0.0394 (12)
O40.7585 (6)0.6211 (3)0.2352 (3)0.0315 (10)
O50.7834 (6)0.6436 (4)0.0469 (4)0.0384 (11)
Mn10.50000.00000.00000.0327 (4)
O60.1953 (6)0.0535 (4)−0.0541 (4)0.0428 (13)
H6C0.15230.05030.01510.051*
H6B0.14850.1267−0.07060.051*
O70.5193 (6)0.1775 (4)0.0174 (4)0.0477 (13)
H7B0.40220.21080.03580.057*
H7C0.59450.16060.07300.057*
O80.3774 (6)−0.0518 (4)0.1787 (4)0.0572 (15)
H8D0.4634−0.04460.22240.069*
H8E0.2674−0.00660.18890.069*
O90.9213 (6)0.2144 (4)0.0353 (4)0.0465 (13)
H9D0.90920.20920.10700.056*
H9B0.82590.26170.00080.056*
O100.6740 (7)0.8222 (4)0.3246 (4)0.0500 (14)
H10F0.69940.76070.29710.060*
O11A0.0288 (7)0.0311 (4)0.7410 (4)0.0554 (15)
H11B0.11590.07000.75440.066*
H11C0.0589−0.03540.74540.066*
H10E0.662 (10)0.759 (6)0.387 (6)0.06 (2)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0346 (5)0.0328 (5)0.0247 (5)−0.0031 (4)−0.0013 (4)−0.0065 (4)
C10.0277 (19)0.054 (2)0.029 (2)−0.0056 (18)−0.0004 (18)−0.0161 (19)
C20.029 (2)0.057 (2)0.036 (2)−0.005 (2)−0.0012 (19)−0.020 (2)
C30.029 (2)0.063 (3)0.034 (2)−0.005 (2)−0.001 (2)−0.022 (2)
C40.031 (2)0.069 (3)0.034 (2)−0.007 (2)0.000 (2)−0.017 (2)
C50.031 (2)0.066 (3)0.032 (2)−0.007 (2)0.001 (2)−0.011 (2)
C60.028 (2)0.055 (2)0.028 (2)−0.0085 (19)−0.0002 (18)−0.0124 (19)
C70.030 (2)0.050 (2)0.030 (2)−0.009 (2)0.000 (2)−0.006 (2)
C80.029 (2)0.039 (2)0.031 (2)−0.006 (2)−0.002 (2)−0.005 (2)
C90.027 (2)0.035 (2)0.031 (2)−0.006 (2)−0.0011 (19)−0.004 (2)
C100.024 (2)0.032 (2)0.027 (2)−0.003 (2)0.000 (2)−0.005 (2)
C110.025 (2)0.032 (2)0.029 (2)−0.002 (2)0.0010 (19)−0.0042 (19)
C120.053 (4)0.061 (4)0.058 (4)−0.006 (3)−0.004 (3)−0.033 (4)
N10.028 (2)0.041 (2)0.027 (2)−0.0088 (19)−0.0008 (19)−0.009 (2)
N20.024 (2)0.031 (2)0.029 (2)−0.0047 (19)−0.0009 (18)−0.0025 (19)
O10.041 (2)0.058 (3)0.044 (2)−0.005 (2)−0.0023 (19)−0.024 (2)
O20.035 (2)0.050 (2)0.030 (2)−0.0042 (19)−0.0017 (19)−0.013 (2)
O30.046 (3)0.035 (3)0.036 (3)−0.001 (2)−0.001 (2)−0.010 (2)
O40.034 (2)0.030 (2)0.029 (2)−0.0028 (18)0.0010 (18)−0.0058 (18)
O50.039 (3)0.039 (3)0.031 (2)0.000 (2)0.000 (2)−0.001 (2)
Mn10.0291 (9)0.0317 (9)0.0351 (9)−0.0001 (7)−0.0035 (7)−0.0055 (7)
O60.029 (3)0.052 (3)0.047 (3)0.005 (2)−0.007 (2)−0.016 (3)
O70.042 (3)0.038 (3)0.061 (3)0.007 (2)−0.016 (2)−0.011 (3)
O80.036 (3)0.084 (4)0.041 (3)0.004 (3)−0.001 (2)−0.001 (3)
O90.051 (3)0.048 (3)0.039 (3)0.006 (2)−0.011 (2)−0.013 (3)
O100.064 (4)0.034 (3)0.052 (4)−0.011 (3)−0.006 (3)−0.008 (3)
O11A0.050 (3)0.043 (3)0.074 (4)−0.010 (2)0.003 (3)−0.016 (3)
Geometric parameters (Å, °) top
Cu1—O21.873 (4)C10—H10A0.9700
Cu1—N21.887 (5)C10—H10B0.9700
Cu1—N11.905 (5)C11—O51.237 (7)
Cu1—O41.979 (4)C11—O41.282 (7)
C1—O21.323 (7)C12—O11.424 (7)
C1—C21.400 (8)C12—H12A0.9600
C1—C61.418 (9)C12—H12B0.9600
C2—O11.366 (8)C12—H12C0.9600
C2—C31.382 (9)Mn1—O6i2.161 (4)
C3—C41.383 (9)Mn1—O62.161 (4)
C3—H30.9300Mn1—O7i2.173 (4)
C4—C51.360 (8)Mn1—O72.173 (4)
C4—H40.9300Mn1—O8i2.212 (4)
C5—C61.421 (9)Mn1—O82.212 (4)
C5—H50.9300O6—H6C0.8500
C6—C71.434 (8)O6—H6B0.8500
C7—N11.280 (7)O7—H7B0.8500
C7—H70.9300O7—H7C0.8499
C8—N11.479 (7)O8—H8D0.8499
C8—C91.513 (8)O8—H8E0.8499
C8—H8A0.9700O9—H9D0.8500
C8—H8B0.9700O9—H9B0.8500
C9—O31.256 (7)O10—H10F0.8500
C9—N21.290 (7)O10—H10E0.93 (7)
C10—N21.447 (7)O11A—H11B0.8495
C10—C111.513 (8)O11A—H11C0.7651
O2—Cu1—N2179.5 (2)O4—C11—C10117.6 (6)
O2—Cu1—N196.4 (2)O1—C12—H12A109.5
N2—Cu1—N183.4 (2)O1—C12—H12B109.5
O2—Cu1—O496.16 (18)H12A—C12—H12B109.5
N2—Cu1—O484.08 (19)O1—C12—H12C109.5
N1—Cu1—O4167.49 (18)H12A—C12—H12C109.5
O2—C1—C2118.0 (6)H12B—C12—H12C109.5
O2—C1—C6123.8 (6)C7—N1—C8121.0 (6)
C2—C1—C6118.2 (6)C7—N1—Cu1124.9 (5)
O1—C2—C3124.6 (6)C8—N1—Cu1114.1 (4)
O1—C2—C1114.6 (6)C9—N2—C10124.9 (5)
C3—C2—C1120.7 (7)C9—N2—Cu1119.8 (5)
C2—C3—C4121.7 (7)C10—N2—Cu1115.3 (4)
C2—C3—H3119.2C2—O1—C12118.2 (5)
C4—C3—H3119.2C1—O2—Cu1125.7 (4)
C5—C4—C3118.6 (7)C11—O4—Cu1114.0 (4)
C5—C4—H4120.7O6i—Mn1—O6180.0 (4)
C3—C4—H4120.7O6i—Mn1—O7i91.61 (16)
C4—C5—C6122.1 (7)O6—Mn1—O7i88.39 (16)
C4—C5—H5118.9O6i—Mn1—O788.39 (16)
C6—C5—H5118.9O6—Mn1—O791.61 (16)
C1—C6—C5118.6 (6)O7i—Mn1—O7180.0 (2)
C1—C6—C7124.0 (6)O6i—Mn1—O8i89.94 (16)
C5—C6—C7117.4 (6)O6—Mn1—O8i90.06 (16)
N1—C7—C6125.3 (7)O7i—Mn1—O8i92.27 (17)
N1—C7—H7117.4O7—Mn1—O8i87.73 (17)
C6—C7—H7117.4O6i—Mn1—O890.06 (16)
N1—C8—C9109.0 (5)O6—Mn1—O889.94 (16)
N1—C8—H8A109.9O7i—Mn1—O887.73 (17)
C9—C8—H8A109.9O7—Mn1—O892.27 (17)
N1—C8—H8B109.9O8i—Mn1—O8180.0 (4)
C9—C8—H8B109.9Mn1—O6—H6C89.0
H8A—C8—H8B108.3Mn1—O6—H6B119.0
O3—C9—N2127.5 (6)H6C—O6—H6B90.0
O3—C9—C8118.8 (5)Mn1—O7—H7B109.3
N2—C9—C8113.7 (6)Mn1—O7—H7C99.5
N2—C10—C11109.1 (5)H7B—O7—H7C110.9
N2—C10—H10A109.9Mn1—O8—H8D108.6
C11—C10—H10A109.9Mn1—O8—H8E109.3
N2—C10—H10B109.9H8D—O8—H8E109.5
C11—C10—H10B109.9H9D—O9—H9B112.9
H10A—C10—H10B108.3H10F—O10—H10E74.7
O5—C11—O4123.7 (6)H11B—O11A—H11C118.5
O5—C11—C10118.7 (5)
Symmetry codes: (i) −x+1, −y, −z.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O11A—H11C···O3ii0.771.932.689 (6)172
O11A—H11B···O10iii0.852.062.786 (7)143
O10—H10F···O40.851.932.775 (6)180
O10—H10E···O20.93 (7)1.92 (7)2.805 (7)157 (6)
O9—H9D···O30.851.882.727 (6)179
O9—H9B···O70.852.402.842 (6)113
O8—H8E···O11Aiv0.852.122.786 (6)135
O8—H8D···O10v0.852.172.795 (7)130
O7—H7C···O90.852.352.842 (6)117
O7—H7B···O5vi0.852.062.702 (6)132
O6—H6B···O9vii0.852.172.739 (5)124
Symmetry codes: (ii) −x+1, −y, −z+1; (iii) −x+1, −y+1, −z+1; (iv) −x, −y, −z+1; (v) x, y−1, z; (vi) −x+1, −y+1, −z; (vii) x−1, y, z.
Table 1
Selected geometric parameters (Å) top
Cu1—O21.873 (4)Mn1—O62.161 (4)
Cu1—N21.887 (5)Mn1—O72.173 (4)
Cu1—N11.905 (5)Mn1—O82.212 (4)
Cu1—O41.979 (4)
Table 2
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O11A—H11C···O3i0.771.932.689 (6)172
O11A—H11B···O10ii0.852.062.786 (7)143
O10—H10F···O40.851.932.775 (6)180
O10—H10E···O20.93 (7)1.92 (7)2.805 (7)157 (6)
O9—H9D···O30.851.882.727 (6)179
O9—H9B···O70.852.402.842 (6)113
O8—H8E···O11Aiii0.852.122.786 (6)135
O8—H8D···O10iv0.852.172.795 (7)130
O7—H7C···O90.852.352.842 (6)117
O7—H7B···O5v0.852.062.702 (6)132
O6—H6B···O9vi0.852.172.739 (5)124
Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x+1, −y+1, −z+1; (iii) −x, −y, −z+1; (iv) x, y−1, z; (v) −x+1, −y+1, −z; (vi) x−1, y, z.
Acknowledgements top

The authors thank the Natural Science Foundation of Zhejiang Province (grant No. Y4080342) and the Science Foundation of Zhejiang Sci-Tech University (grant No. 0813622-Y) for financial support.

references
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